$bgColor:#0af;
$vm_fontsize:75;
@function rem($px){
    @return ($px / $vm_fontsize) * 1rem;
}
$vm_design: 750;
html {
    font-size: ($vm_fontsize / ($vm_design / 2)) * 100vw; 
    // 同时，通过Media Queries 限制根元素最大最小值
    @media screen and (max-width: 320px) {
        font-size: 64px;
    }
    @media screen and (min-width: 540px) {
        font-size: 108px;
    }
}
// body 也增加最大最小宽度限制，避免默认100%宽度的 block 元素跟随 body 而过大过小
body {
    max-width: 540px;
    min-width: 320px;
}
@mixin ellipsis {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

@mixin border($borderColor){
    position: relative;

    &::after{
        content: "";
        position: absolute;
        bottom: 0;
        left: 0;
        width: 100%;
        border-top: 1px solid $borderColor;
    }
}

@media (min-device-pixel-ratio: 1.5) {
    .border{

        &::after{
            transform: scaleY(0.7);
        }
    }
}

@media (min-device-pixel-ratio: 2) {
    .border{

        &::after{
            transform: scaleY(0.5);
        }
    }
}